Covalent bonds share electrons with each other.
There are two type of covalent bonds:
Polar: When a covalent bond is polar one of the atoms has a stronger pull on the elctrons. This means this same atom has a higher elctronegativity value then the other atom.
In order for it to be a polar bond then when subtractin the elctromagnetic value has to be .3-1.7
Nonpolar: If when subtracting the elctronegativity values the difference is less then .3 then the bound is nonpolar, and the pull on the electrons are too closely even to make a difference.
If the difference is more then 1.7 then it is an ionic bond.
Electronegativity increase up and to the right.
The Shapes of Molecules
Molecular Geometry describes the 3-D arrangement of atoms in a molecule.
Linear= 2 electron pairs(bonds) ex.CO2
Trigonal Planar=3 electron pairs(bonds) ex.BH3
Angular bent=2 bonds an electron pair ex.SO2
Tetrahedral=4 electron bonds ex.CH4
Trigonal Pyramidal=3 electron bonds 1 electron pair ex.NH3
Bent=2 electron pairs and 2 electron bonds ex.H2O
REVIEW DIAGRAMS!!
1) Which of the following is a covalent compound?
A. Na2O
B. CaCl2 C. Cl2O
D. CsCl
E. Al2O3 When subtracting the electronegativity values the difference was .5 which is between o-1.7 making it covalent.
2) Which of the following contains covalent bonds?
A. BaO B. IBr
C. Mg
D. LiBr
E. Cu The difference is .3 which is between 0-1.7.
3) In which of these substances are the atoms held together by polar covalent bonding?
A. SrCl2
B. CsCl C. ClF
D. TiF2
E. S8 The difference is less then or equal to 1.7, but great then .3.
4) Electronegativity is a measure of
A. the energy needed to remove an electron from an atom.
B. the energy released when an electron is added to an atom.
C. the magnitude of the negative charge on an electron. D. the attraction by an atom for electrons in a chemical bond.
E. the magnitude of the negative charge on a molecule. It is the pull of an atoms electrons!!
5) Which of the following elements is the most electronegative? A. S
B. Ru
C. Si
D. Te
E. Cs Sulfer has the highest electroneagtivity value because it is the farthest to the top and right of the periodic table.
6) Which of the following elements is the least electronegative?
A. Si
B. Se
C. S
D. Sc E. Sr It is the farthest to the left and down.
7) Which of the following elements is the most electronegative?
A. Ne
B. Rb
C. P
D. I Cl and P are the same height but since Cl is more to the right it has the higher electronegativity.
8) Arrange aluminum, nitrogen, phosphorus and indium in order of increasing electronegativity.
A. Al < In < N < P B. Al < In < P < N
C. In < Al < P < N
D. In < P < Al < N
E. None of these orders is correct.
From left to right, and down to up puts them in the right order.
9) Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity.
A. S > As > Rb > Ca B. S > As > Ca > Rb
C. As > S > Rb > Ca
D. As > S > Ca > Rb
E. None of these orders is correct.
From right to left, and up to down puts them in the right order since now they are decreasing.
10) Select the most polar bond amongst the following.
A. C-O
B. Si-F
C. Cl-F D. C-F
E. C-I
It has a differnce of 1/5, which is closest to the polar value of 1.7
11) According to VSEPR theory, a molecule with the general formula AX2 will have a _ molecular shape. A. linear
B. bent
C. trigonal planar
D. tetrahedral
E. triangular With two Xs comming off, then it forms a line making it linear. 12) According to VSEPR theory, a molecule with the general formula AX3 will have a molecular shape.
A. linear
B. bent C. trigonal planar
D. tetrahedral
E. trigonal pyramidal If you draw the diagram then it will have A in the middle with 3 Xs coming off it.
13) According to VSEPR theory, a molecule with the general formula AX4 will have a __ molecular shape.
A. bent
B. trigonal planar
C. trigonal pyramidal
D. square planar E. tetrahedral
An A in the middle and 4 Xs comming off it.
14) What is the molecular shape of N2O as predicted by the VSEPR theory?
A. trigonal pyramidal
B. trigonal planar
C. angular
D. bent E. linear
It is linear because when the electrons are paired it makes a line. Also, you have to add an extra electron to oxygen for it to work making it negative.
15) What is the molecular shape of the thiocyanate anion, SCN-, as predicted by the VSEPR theory? (Carbon is the central atom.) A. linear
B. bent
C. angular
D. trigonal
E. none of these choices is correct It is linear because when the electrons are paired it makes a line. Also, you have to add an extra two electron to Nitrogen for it to work making it negative.
16) What is the molecular shape of ClCN as predicted by the VSEPR theory? (Carbon is the central atom.) A. linear
B. bent
C. angular
D. trigonal
E. none of these choices is correct
They form a line when connected.
17) What is the molecular shape of BeH2 as predicted by the VSEPR theory? A. linear
B. bent
C. angular
D. trigonal
E. none of these choices is correct they form a line because they push against each other and want to be as far apart as possible.
There are two type of covalent bonds:
Polar: When a covalent bond is polar one of the atoms has a stronger pull on the elctrons. This means this same atom has a higher elctronegativity value then the other atom.
In order for it to be a polar bond then when subtractin the elctromagnetic value has to be .3-1.7
Nonpolar: If when subtracting the elctronegativity values the difference is less then .3 then the bound is nonpolar, and the pull on the electrons are too closely even to make a difference.
If the difference is more then 1.7 then it is an ionic bond.
Electronegativity increase up and to the right.
The Shapes of Molecules
Molecular Geometry describes the 3-D arrangement of atoms in a molecule.
Linear= 2 electron pairs(bonds) ex.CO2
Trigonal Planar=3 electron pairs(bonds) ex.BH3
Angular bent=2 bonds an electron pair ex.SO2
Tetrahedral=4 electron bonds ex.CH4
Trigonal Pyramidal=3 electron bonds 1 electron pair ex.NH3
Bent=2 electron pairs and 2 electron bonds ex.H2O
REVIEW DIAGRAMS!!
1) Which of the following is a covalent compound?
A. Na2O
B. CaCl2
C. Cl2O
D. CsCl
E. Al2O3
When subtracting the electronegativity values the difference was .5 which is between o-1.7 making it covalent.
2) Which of the following contains covalent bonds?
A. BaO
B. IBr
C. Mg
D. LiBr
E. Cu
The difference is .3 which is between 0-1.7.
3) In which of these substances are the atoms held together by polar covalent bonding?
A. SrCl2
B. CsCl
C. ClF
D. TiF2
E. S8
The difference is less then or equal to 1.7, but great then .3.
4) Electronegativity is a measure of
A. the energy needed to remove an electron from an atom.
B. the energy released when an electron is added to an atom.
C. the magnitude of the negative charge on an electron.
D. the attraction by an atom for electrons in a chemical bond.
E. the magnitude of the negative charge on a molecule.
It is the pull of an atoms electrons!!
5) Which of the following elements is the most electronegative?
A. S
B. Ru
C. Si
D. Te
E. Cs
Sulfer has the highest electroneagtivity value because it is the farthest to the top and right of the periodic table.
6) Which of the following elements is the least electronegative?
A. Si
B. Se
C. S
D. Sc
E. Sr
It is the farthest to the left and down.
7) Which of the following elements is the most electronegative?
A. Ne
B. Rb
C. P
D. I
Cl and P are the same height but since Cl is more to the right it has the higher electronegativity.
8) Arrange aluminum, nitrogen, phosphorus and indium in order of increasing electronegativity.
A. Al < In < N < P
B. Al < In < P < N
C. In < Al < P < N
D. In < P < Al < N
E. None of these orders is correct.
From left to right, and down to up puts them in the right order.
9) Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity.
A. S > As > Rb > Ca
B. S > As > Ca > Rb
C. As > S > Rb > Ca
D. As > S > Ca > Rb
E. None of these orders is correct.
From right to left, and up to down puts them in the right order since now they are decreasing.
10) Select the most polar bond amongst the following.
A. C-O
B. Si-F
C. Cl-F
D. C-F
E. C-I
It has a differnce of 1/5, which is closest to the polar value of 1.7
11) According to VSEPR theory, a molecule with the general formula AX2 will have a _ molecular shape.
A. linear
B. bent
C. trigonal planar
D. tetrahedral
E. triangular
With two Xs comming off, then it forms a line making it linear.
12) According to VSEPR theory, a molecule with the general formula AX3 will have a molecular shape.
A. linear
B. bent
C. trigonal planar
D. tetrahedral
E. trigonal pyramidal
If you draw the diagram then it will have A in the middle with 3 Xs coming off it.
13) According to VSEPR theory, a molecule with the general formula AX4 will have a __ molecular shape.
A. bent
B. trigonal planar
C. trigonal pyramidal
D. square planar
E. tetrahedral
An A in the middle and 4 Xs comming off it.
14) What is the molecular shape of N2O as predicted by the VSEPR theory?
A. trigonal pyramidal
B. trigonal planar
C. angular
D. bent
E. linear
It is linear because when the electrons are paired it makes a line. Also, you have to add an extra electron to oxygen for it to work making it negative.
15) What is the molecular shape of the thiocyanate anion, SCN-, as predicted by the VSEPR theory? (Carbon is the central atom.)
A. linear
B. bent
C. angular
D. trigonal
E. none of these choices is correct
It is linear because when the electrons are paired it makes a line. Also, you have to add an extra two electron to Nitrogen for it to work making it negative.
16) What is the molecular shape of ClCN as predicted by the VSEPR theory? (Carbon is the central atom.)
A. linear
B. bent
C. angular
D. trigonal
E. none of these choices is correct
They form a line when connected.
17) What is the molecular shape of BeH2 as predicted by the VSEPR theory?
A. linear
B. bent
C. angular
D. trigonal
E. none of these choices is correct
they form a line because they push against each other and want to be as far apart as possible.